Indeed, some people concentrate better when they’re able to fidget. And while “restless leg syndrome” sounds like it could explain this type of behavior, it’s actually something completely different, reports Refinery29.

Restless leg syndrome is a neurological condition, which means any sensations it causes happen in the brain more than in the legs themselves. And while it is defined by an “irresistible urge to move the legs,” according to Andy Berkowski, MD, a clinical assistant professor of neurology and sleep medicine at the University of Michigan Department of Neurology, it’s not related to a general inability to sit still.

If you’re sitting at your desk for long periods of time, you might get uncomfortable or anxious because you haven’t stretched or moved around. But with restless leg syndrome, people don’t feel generally restless, they feel specifically restless in their legs, he says.